Preparation and application of blade array CoPVOx catalytic material

Abstract

The invention relates to the technical field of preparation of green energy catalytic electrode materials, in particular to preparation and application of a blade array CoPVOx catalytic material. The CoPVOx catalytic material is successfully prepared through a one-step hydrothermal method, the preparation method is simple and convenient, and the CoPVOx material has a blade array structure formed by stacking a large number of nanosheets and is high in specific surface area and multiple in active sites, so that the catalytic activity is high; on the basis, the invention also provides an application of the CoPVOx catalytic material in electro-catalytic hydrogen evolution, and a result shows that the overpotential of the CoPVOx electrode is not obviously increased when the CoPVOx electrode is subjected to a hydrogen evolution reaction for 50 hours in a 100 mA / cm < 2 > constant current mode. Therefore, the CoPVOx blade array electrode prepared by the method has excellent electro-catalytic hydrogen evolution performance and stability, and provides a new direction for the field of electro-catalytic hydrogen evolution energy.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of green energy catalytic electrode material preparation, and particularly relates to preparation and application of a blade array CoPVOx catalytic material. BACKGROUND

[0002] Energy is the basis for the survival and development of human society, and it occupies an important position in the national economy. With the intensification of global energy crisis and the enhancement of environmental protection consciousness, it is inevitable to develop efficient and clean energy conversion technology. As an ideal green energy carrier, hydrogen energy has the advantages of high energy density, clean and pollution-free, and can be stored and transported, and as a sustainable energy storage method, electrocatalytic hydrogen evolution has attracted widespread attention.

[0003] In electrocatalytic hydrogen evolution, efficient catalysts can reduce the overpotential of the reaction and improve the energy utilization efficiency. In recent years, researchers have prepared electrocatalytic hydrogen evolution materials by various methods and optimized their performance. For example, in a CoP / Si hydrogen evolution catalytic material and a preparation method thereof disclosed in Chinese patent CN110882707 A, a CoP / Si hydrogen evolution catalytic material is prepared by sequentially pre-treating the surface of a silicon wafer, preparing a Si-Co salt precursor by electrodeposition, and high-temperature phosphating, thereby optimizing the photoelectrocatalytic hydrogen evolution performance; and for another example, Chinese patent CN 108380227 A discloses a hydrogen evolution electrocatalytic material and a preparation method thereof, specifically: red phosphorus and self-made spherical metal nickel powder and non-metallic conductive materials are used as raw materials, a tablet press is used for pre-forming treatment, and a three-dimensional porous self-supporting nickel phosphide hydrogen evolution electrocatalytic material is prepared by in-situ reaction of the uniformly mixed raw materials at high temperature. The material has strong electrocatalytic hydrogen evolution stability. Although the above-mentioned schemes optimize the hydrogen evolution performance of the catalytic material to different extents, they still have the pain points of unsatisfactory hydrogen evolution effect and complex preparation method.

[0004] In addition, existing technology research has found that although the blade array CoPVOx catalytic material has a high specific surface area and good electrical conductivity, it can provide more active sites, enhance the contact between the catalyst and the reactants, and improve the hydrogen production efficiency. However, there are few reports on how to simply and quickly prepare CoPVOx catalytic material, and how to improve its performance under high current density and enhance its stability in complex environment are still key problems to be solved at present. SUMMARY

[0005] The purpose of the present application is to provide a preparation and application of a blade array CoPVOx catalytic material, which has a simple preparation method, good catalytic activity, and strong hydrogen evolution stability.

[0006] The application provides a method for preparing a blade array CoPVOx catalytic material, comprising the following steps: (1) soaking the foamed nickel in a hydrochloric acid solution, washing, and obtaining pretreated foamed nickel; (2) dissolving Co(NO3)2.6H2O in deionized water to obtain solution A; (3) dissolving NH4H2PO4 and KVO3 in deionized water to obtain solution B; (4) adding the solution B dropwise into the solution A to obtain a suspension C; (5) transferring the suspension C and the pretreated foamed nickel into a high-pressure reaction kettle, hydrothermally treating, naturally cooling, washing, and drying to obtain a blade array CoPVOx sample.

[0007] Preferably, when the foamed nickel is soaked in the hydrochloric acid, the concentration of the hydrochloric acid is 0.5-0.6 M.

[0008] Preferably, the soaking parameters include that the time is 30-40 min and the temperature is 25-30 DEG C.

[0009] Preferably, the washing processes in the step (1) and the step (5) respectively include that the material to be washed is alternately washed with deionized water and ethanol. The volume concentration of the ethanol is 90%-95%.

[0010] Preferably, in the solution A, the concentration of Co(NO3)2.6H2O is 0.1-0.3 M.

[0011] Preferably, in the solution B, the concentration of NH4H2PO4 is 0.05-0.15 M, and the concentration of KVO3 is 0.05-0.15 M.

[0012] Preferably, the hydrothermal treatment parameters include that the temperature is 140-200 DEG C and the time is 14-24 h.

[0013] Preferably, the drying is performed in a vacuum drying box, and the drying parameters include that the temperature is 50-60 DEG C and the time is 4-6 h.

[0014] The application provides a blade array CoPVOx catalytic material prepared by the method.

[0015] The application provides application of the blade array CoPVOx catalytic material in electrocatalytic hydrogen evolution.

[0016] Beneficial effects: The application provides a method for preparing a blade array CoPVOx catalytic material, comprising the following steps: (1) soaking a foamed nickel in a hydrochloric acid solution, washing, and obtaining pretreated foamed nickel; (2) dissolving Co(NO3)2.6H2O in deionized water to obtain solution A; (3) dissolving NH4H2PO4 and KVO3 in deionized water to obtain solution B; (4) adding the solution B dropwise into the solution A to obtain a suspension C; (5) transferring the suspension C and the pretreated foamed nickel into a high-pressure reaction kettle, and hydrothermally treating, naturally cooling, washing, and drying to obtain a blade array CoPVOx sample.

[0017] The blade array CoPVOx catalytic material prepared by the technical scheme has excellent electrocatalytic hydrogen evolution performance. 2

[0018] Compared with the prior art, the application has the following beneficial effects: (1) The CoPVOx catalytic material is successfully prepared by the one-step hydrothermal method, has a large number of nanometer flake accumulated blade array structure, and the surface size and thickness of the CoPVOx are obviously smaller than those of CoVOx and CoPOx.

[0019] (2) The CoPVOx electrode provided by the application has a hydrogen evolution overpotential of 70 mV, 236 mV and 361 mV under current densities of 10 mA / cm 2 , 100 mA / cm 2 and 500 mA / cm 2 , respectively, and the overpotential does not obviously increase under the constant current mode of 100 mA / cm 2 for 50 h. BRIEF DESCRIPTION OF DRAWINGS

[0020] In order to more clearly illustrate the technical solutions in the embodiments of the application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments. Obviously, the drawings in the following description are only some embodiments of the application, and for those skilled in the art, other drawings can be obtained based on these drawings without creative labor. ​

[0021] Figure 1 XRD patterns of CoPOx, CoVOx and CoPVOx provided by the present application; Figure 2 SEM pictures of CoPOx, CoVOx and CoPVOx materials provided by the present application; Figure 3 Electrochemical polarization curve diagrams of CoPOx, CoVOx and CoPVOx electrodes provided by the present application; Figure 4 Hydrogen evolution overpotential column charts of CoPOx, CoVOx and CoPVOx electrodes provided by the present application under different current densities; Figure 5 Water electrolysis hydrogen evolution reaction stability of CoPVOx electrodes provided by the present application. DETAILED DESCRIPTION

[0022] In order to further illustrate the present application, the schemes provided by the present application are described in detail below in combination with the drawings and examples, but they cannot be understood as limiting the scope of protection of the present application.

[0023] Example 1 A preparation method of a blade array CoPVOx catalytic material, namely one-step hydrothermal method, steps are as follows: (1) At 25 °C, foam nickel (denoted as NF, area is 1×2 cm 2 ) is immersed in 0.5 M hydrochloric acid for pretreatment for 30 min, and then the foam nickel is washed with ionized water and then with 95% by volume ethanol to obtain pretreated foam nickel.

[0024] (2) Under magnetic stirring, 1 mmol of Co(NO3)2·6H2O is dissolved in 7 mL of deionized water to form a transparent solution to obtain solution A; Under magnetic stirring, 0.5 mmol of NH4H2PO4 and 0.5 mmol of KVO3 are dissolved in 5 mL of deionized water to obtain solution B; Under magnetic stirring, solution B is added dropwise to solution A and mixed uniformly to obtain suspension C.

[0025] (3) The pretreated NF is mixed with suspension C and transferred to a sealed high-pressure reaction kettle, heated at 180 °C for 18 h, and then naturally cooled to room temperature, the sample is taken out, washed with ionized water first and then with 95% by volume ethanol, and dried in a vacuum drying box at 60 °C for 4 h to obtain a CoPVOx sample.

[0026] Comparative Example 1 A preparation method of CoPOx catalytic material, steps are as follows: (1) The nickel foam (denoted as NF, with an area of 1 x 2 cm 2 ) was pretreated by immersing in 0.5 M hydrochloric acid at 25 °C for 30 min, and then washed with ionized water and 95% (by volume) ethanol to obtain pretreated nickel foam.

[0027] (2) 1 mmol of Co(N03)2.6H20 was dissolved in 7 mL of deionized water under magnetic stirring to form a transparent solution to obtain solution A; 0.5 mmol of NH4H2P04 was dissolved in 5 mL of deionized water under magnetic stirring to obtain solution B; Solution B was added dropwise to solution A under magnetic stirring, and mixed uniformly to obtain suspension C.

[0028] (3) The pretreated NF was mixed with suspension C, transferred into a sealed high-pressure reaction kettle, heated at 180 °C for 18 h, and then naturally cooled to room temperature. The sample was taken out, washed with ionized water and 95% (by volume) ethanol, and dried in a vacuum drying oven at 60 °C for 4 h to obtain a CoPOx sample.

[0029] Comparative Example 2 The preparation method of the CoVOx catalytic material includes the following steps: (1) The nickel foam (denoted as NF, with an area of 1 x 2 cm 2 ) was pretreated by immersing in 0.5 M hydrochloric acid at 25 °C for 30 min, and then washed with ionized water and 95% (by volume) ethanol to obtain pretreated nickel foam.

[0030] (2) 1 mmol of Co(N03)2.6H20 was dissolved in 7 mL of deionized water under magnetic stirring to form a transparent solution to obtain solution A; 0.5 mmol of KVO3 was dissolved in 5 mL of deionized water under magnetic stirring to obtain solution B; Solution B was added dropwise to solution A under magnetic stirring, and mixed uniformly to obtain suspension C.

[0031] (3) The pretreated NF was mixed with suspension C, transferred into a sealed high-pressure reaction kettle, heated at 180 °C for 18 h, and then naturally cooled to room temperature. The sample was taken out, washed with ionized water and 95% (by volume) ethanol, and dried in a vacuum drying oven at 60 °C for 4 h to obtain a CoVOx sample.

[0032] Material characterization The CoPOx prepared in Comparative Example 1, the CoVOx prepared in Comparative Example 2 and the CoPVOx prepared in Example 1 were respectively subjected to XRD spectrum analysis, and the results are shown in Figure 1 .

[0033] It can be seen from Figure 1 that the characteristic diffraction peaks of the CoPOx match the standard card of monoclinic Co6P4O 20 (JCPDS No. 96-100-0102), the CoVOx material is mainly composed of monoclinic CoO8V3 (JCPDS No. 00-022-0599) and monoclinic Co2O7V2 (JCPDS No. 00-029-0519), and the characteristic diffraction peaks of the CoPOx and the CoVOx are simultaneously detected in the CoPVOx material, which indicates that the CoPOx / CoVOx composite catalytic material is successfully prepared by the one-step hydrothermal method.

[0034] The CoPOx prepared in Comparative Example 1, the CoVOx prepared in Comparative Example 2 and the CoPVOx prepared in Example 1 were respectively subjected to SEM analysis, and the results are shown in Figure 2 (in Figure 2 , a represents the SEM result of the CoPOx; b represents the SEM result of the CoVOx; and c represents the SEM result of the CoPVOx).

[0035] As can be seen from the a graph of Figure 2 , the CoPOx prepared by the hydrothermal method has a long spear array structure; Figure 2 the b graph shows that the CoVOx obtained by the hydrothermal reaction has a cubic columnar block structure; Figure 2 the c graph is an SEM photograph of the CoPVOx material. It can be clearly seen that the CoPVOx has a large number of nanosheet accumulated knife array structure, and the surface size and thickness of the CoPVOx are obviously smaller than those of the CoVOx and the CoPOx, which is beneficial to increase the specific surface area of the CoPVOx material and expose more catalytically active sites, thereby improving the catalytic activity thereof.

[0036] Performance test The hydrogen evolution performance of the electrode material prepared in the application was evaluated by taking a Hg / HgO electrode as a reference electrode, taking a graphite rod as a counter electrode, taking the prepared electrode material as a working electrode, and taking a 1.0 M KOH solution as an electrolyte.

[0037] The CoPOx prepared in Comparative Example 1, the CoVOx prepared in Comparative Example 2 and the CoPVOx prepared in Example 1 were respectively subjected to electrode electrochemical polarization curve analysis, and the results are shown in Figure 3 ; at 10 mA / cm 2, 100 mA / cm 2 and 500 mA / cm 2 The hydrogen evolution overpotential analysis was carried out at different current densities. The results are shown in Figure 4 .

[0038] Depend on Figure 3 It can be seen that the hydrogen evolution performance of CoPVOx electrode is significantly better than that of CoPOx and CoVOx electrodes; Figure 4 It can be seen that at 10 mA / cm 2 , 100 mA / cm 2 and 500 mA / cm 2 The overpotentials of hydrogen evolution of CoPVOx electrode at different current densities were 70 mV, 236 mV and 361 mV, respectively, which were significantly lower than those of CoPOx and CoVOx electrodes under the same conditions. 2 At the current density, the hydrogen evolution overpotential of the CoPVOx electrode is lower than that of commercial Pt / C, indicating that the prepared CoPVOx blade array electrode has excellent electrocatalytic hydrogen evolution performance.

[0039] The stability of the CoPVOx prepared in Example 1 was analyzed by electrolysis of water and hydrogen evolution reaction. Figure 5 .

[0040] Combine Figure 5 It can be seen that the CoPVOx electrode has a high 2 The overpotential did not show a significant increase when the hydrogen evolution reaction was carried out under constant current mode for 50 h, indicating that the prepared CoPVOx blade array electrode has excellent electrocatalytic hydrogen evolution stability.

[0041] Although the above embodiment provides a detailed description of the present invention, it is only a part of the embodiments of the present invention, not all of the embodiments. People can also obtain other embodiments based on this embodiment without creativity, and these embodiments all fall within the scope of protection of the present invention.

Claims

1. A method for preparing a blade array CoPVOx catalytic material, characterized in that: The steps include: (1) soaking the nickel foam in a hydrochloric acid solution and washing it to obtain pretreated nickel foam; (2) Dissolve Co(NO3)2·6H2O in deionized water to obtain solution A; (3) Dissolve NH4H2PO4 and KVO3 in deionized water to obtain solution B; (4) adding the solution B dropwise to the solution A to obtain a suspension C; (5) The suspension C and the pretreated nickel foam are transferred to a high-pressure reactor, hydroheated, naturally cooled, washed, and dried to obtain a blade array CoPVOx sample.

2. The method according to claim 1, characterized in that When the nickel foam is soaked in hydrochloric acid, the concentration of the hydrochloric acid is 0.5-0.6 M.

3. The method according to claim 1 or 2, characterized in that The soaking parameters include: time of 30-40 minutes and temperature of 25-30°C.

4. The method according to claim 1, wherein The washing process in step (1) or step (5) respectively comprises: washing the material to be washed alternately with deionized water and ethanol in sequence; The volume concentration of the ethanol is 90% to 95%.

5. The method according to claim 1, wherein In the solution A, the concentration of Co(NO3)2·6H2O is 0.1~0.3 M.

6. The method according to claim 1, characterized in that In the solution B, the concentration of NH4H2PO4 is 0.05~0.15M; the concentration of KVO3 is 0.05~0.15M.

7. The method according to claim 1, characterized in that The hydrothermal parameters include: temperature of 140-200°C and time of 14-24 hours.

8. The method according to claim 1, characterized in that The mixture was dried in a vacuum drying oven, wherein the drying parameters included: a temperature of 50-60° C. and a drying time of 4-6 h.

9. A blade array CoPVOx catalytic material prepared by the method according to any one of claims 1 to 8.

10. Use of the blade array CoPVOx catalytic material according to claim 9 in electrocatalytic hydrogen evolution.

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